As a technique for efficiently guiding light incident on a window glass into a room, a technique described in PTL 1 has been known. According to the technique of PTL 1, a daylighting film obtained by forming a plurality of unit prisms on one surface of a light-transmissive support is attached to an inner surface (indoor side surface) of the window glass with the unit prisms facing the outside. Light incident from the unit prism side is refracted by surfaces of the unit prisms, transmitted through the unit prisms, the support, and the window glass, and enters into the room.